[wxqc] C4443 Dew Point errors
Dave Helms
dshelms at comcast.net
Sat Jan 7 13:02:16 EST 2006
Hi Martin,
The closest CWOP and airport stations that are available in Philip's QC
database:
http://weather.gladstonefamily.net/qchart/C4443?date=20060107&addnl=C0318&addnl=AR788&addnl=KRVS&addnl=KTUL&addnl=C2570&addnl=AP228&Add+to+charts=Add+to+charts&.cgifields=addnl
None of these stations appear to be the source of the dew point
jaggies. Since WxBug/AWS stations are in "stealth" mode (NOAA gets the
data, but can't post the data on the public domain), its very possible
TLSA2 is the source of the problem (I can't tell if that is the case).
MikeB: Could you please black-list this station in MADIS if it has
way-negative dew point obs?
TLSA2 (AWS) Holland Hall School Tulsa, OK
Thanks,
Dave
CW0351
zmwp01 at valornet.com wrote:
>Good morning Dave,
>It seems another station(may be the same one as below) is causing
>a large shift in the analysis data for my station again. When comparing
>my DP to the two airports and others near me I am very close but the
>analysis data is showing 4-6 degF below all others. I would really like
>for this to be cleared up so the QC graphs have merit again.
>In the meantime I have been using two airports and five nearby
>stations for my reference.
>Thank you,
>Martin
>
>
>
>>Hummm... I had not seen that station before when I looked at your nearby
>>station. Lets see what can be done to get that bugger fixed or gone so
>>it isn't messing up the analysis.
>>
>>Dave
>>CW0351
>>
>> From MADIS: TLSA2 (AWS) Holland Hall School Tulsa, OK
>>time slp t / td dir / spd / gst/pcp presWx &
>>skyCover
>>(UTC) (mb) (F) (mph) (in.)
>>1329 1020.7(S) 29.0(S)/-33.3(S) 120°(C)/002(S)/---/0.00"
>>1314 1021.0(V) 29.0(V)/-33.3(Q) 96°(V)/001(V)/---/0.00"
>>1259 1020.7(V) 28.0(V)/-34.0(Q) 110°(V)/002(V)/---/0.00"
>>1244 1020.7(V) 28.0(V)/-34.0(Q) 100°(V)/002(V)/---/0.00"
>>1224 1020.7(V) 28.0(V)/-34.0(Q) 110°(V)/001(V)/---/0.00"
>>
>>zmwp01 at valornet.com wrote:
>>
>>
>>
>>>Good morning Dave,
>>>
>>>There is a station TLSA2 (Holland Hall School Tulsa,OK) that has
>>>been steadily reporting a dew point value -40 to -50 degF below
>>>the neighboring stations. This station is only a few miles from mine
>>>and may the cause of the offset in my ANALYSIS data.
>>>I discovered that the ANALYSIS data from other stations not so close
>>>to TLSA2 fell right in line with my DP data. A comparison of the other
>>>five closest stations falls in line with my data also.
>>>Hope this is of some help to you.
>>>
>>>Best regards,
>>>Martin
>>>
>>>
>>>
>>>
>>>
>>>>Hi Martin,
>>>>
>>>>When in doubt, use the nearby ASOS stations as your source for truth as
>>>>personal weather station data my not be accurate. The +3F dew point
>>>>bias exists for your station because most of your closest 5 neighbors
>>>>have average dew points as least 3 F less than your average dew point
>>>>most of the time... at least that was the case in your station's
>>>>longer-term analysis statistics, but more recently your data is more in
>>>>line with the other stations.
>>>>
>>>>Much of the time, the QCMS analysis for individual CWOP stations is
>>>>comprised of mix of CWOP and non-CWOP stations. AWS/WxBug folks have
>>>>recently been allowing their data to be views on the MADIS Mesomap, but
>>>>that is not always the case. But even if AWS/WxBug observations are not
>>>>plotting on the MADIS Mesomap, they are likely used in the determination
>>>>of the station analysis (that is, if there are near-by AWS/WxBug
>>>>stations which is generally the case in the more populated areas). My
>>>>point is that it is not always obvious which stations are influencing
>>>>the your station's analysis. When we have questions about the analysis
>>>>input, we generally ask MikeB to that a look at what is going on.
>>>>
>>>>If you are still interested on the details of the MADIS QCMS analysis
>>>>technique, please check out this page especially the spatial
>>>>consistency/OI technique section:
>>>>http://www-sdd.fsl.noaa.gov/MSAS/qcms_descrip.html
>>>>
>>>>
>>>>Regards,
>>>>
>>>>Dave
>>>>CW0351
>>>>
>>>>
>>>>
>>>>zmwp01 at valornet.com wrote:
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>>Good morning Dave,
>>>>>
>>>>>I definitely appreciate your time to help me understand the
>>>>>interpretation
>>>>>of this collected weather data. This has turned out to be
>>>>>a fascinating venture for me. I would have never guess such a network
>>>>>was
>>>>>in place for coordinating and compiling so many weather stations.
>>>>>My hat is off to you, Russ, Philip, and all your team members.
>>>>>I guess what has me puzzled about the +3F error in my humidity is
>>>>>that most of the stations in Tulsa County must have the same error or
>>>>>greater since they usual have a similar reading or higher as
>>>>>illustrated
>>>>>in the link you referenced below. The same can be seen on most other
>>>>>days.
>>>>>I have also been using the NOAA Mesomap for my comparisons.
>>>>>I currently have two weather stations, a Davis VP2+ (6163), which is
>>>>>online with CWOP and a Davis VP2+ (6162) which is not online
>>>>>and being monitored locally. The second station has been moved to
>>>>>different locations on my property to see the effects on the data.
>>>>>So far both stations have been within +/- 1 of each other on most
>>>>>data points when place in the same location.
>>>>>Both stations are only a few months old.
>>>>>This brings to mind the interest in understanding how the ANALYSIS data
>>>>>is
>>>>>generated if it is the only true reference in this case.
>>>>>Your time and effort to help me understand how all this works is
>>>>>much appreciated.
>>>>>
>>>>>Thanks again,
>>>>>Martin
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>>Hi Martin,
>>>>>>
>>>>>>In comparing to the near-by ASOS stations:
>>>>>>http://weather.gladstonefamily.net/qchart/C4443?date=20051129&addnl=KRVS&addnl=KTUL&Add+to+charts=Add+to+charts&.cgifields=addnl
>>>>>>... and the MADIS QCMS ANALYSIS, both show an approximate 3F "moist"
>>>>>>bias. While people have shown cases where the QCMS ANALYSIS has
>>>>>>problems, I believe in this case it is correct. Having a 3F moist
>>>>>>bias
>>>>>>(e.g. the RH and dew point typically are higher than "truth") is just
>>>>>>barely out of spec, so you are still providing reasonably good data
>>>>>>despite the less than perfect humidity observations.
>>>>>>
>>>>>>It is the nature of the thin film capacitor technology (which most
>>>>>>personal weather stations use to sense humidity) to "drift" out of
>>>>>>calibration. What type of weather station hardware do you operate?
>>>>>>
>>>>>>Here is a "classic" thread on diagnosing and resolving humidity
>>>>>>measurement issues which you may wish to peruse:
>>>>>>http://pond1.gladstonefamily.net:8080/pipermail/wxqc/2005-July/subject.html
>>>>>>http://pond1.gladstonefamily.net:8080/pipermail/wxqc/2005-July/000334.html
>>>>>>http://pond1.gladstonefamily.net:8080/pipermail/wxqc/2005-July/000336.html
>>>>>>http://pond1.gladstonefamily.net:8080/pipermail/wxqc/2005-July/000338.html
>>>>>>http://pond1.gladstonefamily.net:8080/pipermail/wxqc/2005-July/000345.html
>>>>>>
>>>>>>
>>>>>>Regards,
>>>>>>
>>>>>>Dave
>>>>>>CW0351
>>>>>>
>>>>>>
>>>>>>
>>>>>>Sam Drinkard wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>>zmwp01 at valornet.com wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>Here are a few links that reference my station CW4443(C4443)
>>>>>>>>http://pond1.gladstonefamily.net:8080/cgi-bin/wxqchart.pl?site=C4443
>>>>>>>>http://www.findu.com/cgi-bin/wxpage.cgi?CW4443
>>>>>>>>http://www.met.utah.edu/cgi-bin/droman/meso_base.cgi?stn=C4443
>>>>>>>>I should have been more specific, sorry.
>>>>>>>>
>>>>>>>>Martin
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>I looked at the graphs, and see first off there is a bad case of the
>>>>>>>"jaggies" in there. Comparing almost all the stations did not reveal
>>>>>>>anyone with really flakey looking lines, but then again, it's hard to
>>>>>>>see so many at one time and my eyes aren't that good :-( From what I
>>>>>>>saw of strictly your data, I don't see anything to indicate a big
>>>>>>>problem. I've certainly seen worse on DP from my own station too. I
>>>>>>>always seem to run a tad too warm on DP, and sometimes too cool with
>>>>>>>temps, but I refuse to try to "fix" the temp problem, as it's still
>>>>>>>within limits. I believe from looking at yours Martin, you are in
>>>>>>>the
>>>>>>>same category I am w/r/t the error(s). The graph for 11/11 does show
>>>>>>>the 5º plus diffs, but is that a spurious reading or anomoly or is
>>>>>>>that what it looks like more times than not?
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>_______________________________________________
>>>>>>wxqc mailing list
>>>>>>wxqc at lists.gladstonefamily.net
>>>>>>http://pond1.gladstonefamily.net:8080/mailman/listinfo/wxqc
>>>>>>
>>>>>>The contents of this message are the responsibility of the author.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>_______________________________________________
>>>>>wxqc mailing list
>>>>>wxqc at lists.gladstonefamily.net
>>>>>http://pond1.gladstonefamily.net:8080/mailman/listinfo/wxqc
>>>>>
>>>>>The contents of this message are the responsibility of the author.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>_______________________________________________
>>>>wxqc mailing list
>>>>wxqc at lists.gladstonefamily.net
>>>>http://pond1.gladstonefamily.net:8080/mailman/listinfo/wxqc
>>>>
>>>>The contents of this message are the responsibility of the author.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>_______________________________________________
>>>wxqc mailing list
>>>wxqc at lists.gladstonefamily.net
>>>http://pond1.gladstonefamily.net:8080/mailman/listinfo/wxqc
>>>
>>>The contents of this message are the responsibility of the author.
>>>
>>>
>>>
>>>
>>>
>>>
>>_______________________________________________
>>wxqc mailing list
>>wxqc at lists.gladstonefamily.net
>>http://pond1.gladstonefamily.net:8080/mailman/listinfo/wxqc
>>
>>The contents of this message are the responsibility of the author.
>>
>>
>>
>
>
>_______________________________________________
>wxqc mailing list
>wxqc at lists.gladstonefamily.net
>http://pond1.gladstonefamily.net:8080/mailman/listinfo/wxqc
>
>The contents of this message are the responsibility of the author.
>
>
>
>
More information about the wxqc
mailing list